WASHINGTON — It’s a sound that jolts most people awake—even from some of the deepest sleep. We hit the snooze button, but the persistent, sometimes annoying, sound of our alarm clocks just won’t quit.

As modern lifestyles increasingly challenge the body's natural circadian rhythm, the American Heart Association is spotlighting the potential health consequences of regular disruptions to our body's ...

Turning the clocks forward an hour in the spring for daylight saving time is followed by a spike in heart attacks on the Monday afterward, said a US study on Saturday. But when the clocks fall back ...